"CEATERS OF THE MOON" STEARNS 309 



epoch, and most of the flows and cones are now buried by later 

 flows. Remnants of these old cones, broken by faulting and weath- 

 ered down into hoodoolike pinnacles of cinders and spatter, form 

 the Devil's Orchard, and the field of crags south of Big Cinder 

 Butte. In these crags occurs obsidian, or volcanic glass, which the 

 Indians quarried to make arrow points and other implements of 

 stone. 



For a long time the Great Rift seemed to be healed, but volcanic 

 activity broke out again with renewed vigor, and many of the large 

 cinder cones in the chain that stretches southeast through the cen- 

 ter of the monument were formed. To this second epoch belong 

 Sunset, Grassy, Silent, Big Cinder, Fissure, Split, and numerous 

 unnamed cones along the Great Rift. Most of their lava flows have 

 been buried by later flows, but the cones rise as islands above them. 

 The volcanic outbursts were spasmodic but probably followed at 

 short intervals. Often more than one cone was formed during a 

 great eruption, and there is evidence that some of the cones were 

 made by successive eruptions occurring at the same place. 



The third and last epoch of eruption followed closely upon (he 

 second and may have been actually closely connected. During this 

 epoch, which is the most recent, all the barren black lavas that are 

 found in the area were emitted. North Crater, visible from the road 

 to Carey, was reopened and gave vent to a large billowy lava flow 

 that moved northward and then eastward. This flow is crossed by 

 the road leading to the registration booth. Big Crater gave vent 

 to four flows during this epoch, to the northeast, northwest, and 

 southeast. With the last eruption of Big Crater the line of spat- 

 ter cones at the end of the motor road was formed and lava flowed 

 east and west from them. With the subsidence of the lava in the 

 Great Rift following this eruption numerous areas along the rift 

 collapsed, forming a chain of pit craters. Big Sink water hole 

 is located in one of these pit craters. Big Cinder Butte broke 

 open again and gave vent to a short lava flow on the north side. Two 

 other outpourings of lava occurred in the area one half-mile north- 

 west of this breach, but the eruptions at these vents did not build 

 cinder cones. Lava also poured out at Indian Tunnel, the Natural 

 Bridge, and at Needles Cave in the area east of Inferno. In tlie 

 central part of the monument the old cinder cone called the Watchman 

 opened and lava flowed out quietly from the northwest and the south- 

 west sides. Altogether 35 cones and vents and 30 different lava 

 flows of various epochs are found in the monument, and many others 

 are probably buried. 



No evidence was found of any great explosive eruption such as 

 occurred at Krakatoa in 1883, or at Katmai in 1912. The volcanic 

 24034—29 21 



